<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8" />
<title>3-1什么是变量</title>
</head>
<body>
    <div align="center">
        <?php
        $var = "大家来学习php";
        echo $var;
        echo "<br />";
        
        $var = "学习php上慕课网";
        echo $var;
        ?>
    </div>
</body>
</html>